Gas burners

ABSTRACT

A gas burner formed from an elongated hollow extrusion having three manifolds formed therein. One of the manifolds comprises a high-pressure manifold delivering raw gas through a series of apertures to the main flame while the second manifold delivers a combustible gas and air mixture through a second series of apertures to the pilot or low-heat flame. The third manifold delivers high-pressure gas through a series of transfer apertures to the second manifold periodically along the entire length of the second manifold. A series of air admission apertures along the second manifold allow air to pass into the gas in the second manifold under the influence of aspiration.

gated hollow n. One of the g raw hile the gas and air mixture pilot orlow-heat -pressure gas through a d manifold periodically series of airigh 2,613,737 10/1952 Schwietert.....

3,051,464 8/1962 Yeo et al.

Primary Examiner-Carroll B. Dority, Jr.

AttorneyRobert M. Dunning ABSTRACT: A gas burner formed from an elonextrusion having three manifolds formed therei manifolds comprises ahigh-pressure manifold deliverin gas through a series of apertures tothe main flame w second manifold delivers a combustible through a secondseries of apertures to the flame. The third manifold delivers h seriesof transfer apertures to the secon along the entire length of the secondmanifold. A

admission apertures along the second manifold allow air to pass into thegas in the second manifold under the influence of aspiration.

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Richard N. Weatherston Saint Paul Minn. 5.166 Jan. 23, 1970 PatentedJuly 13, 1971 Weather-Rite Manufacturing County of Ramsey, Minn.

References Cited UNITED STATES PATENTS 6/1906 lnventor Appl. No.

Filed Assignee 5 Claims, 2 Drawing Figs.

United States Patent [54] GASBURNERS [50] FieldofSearch...

PATENT'EU Jun 319?! lhh INVENTOR R/CHARD /V. WEATHERSTO/V ATTORNEY GASBURNERS BACKGROUND OF THE INVENTION Recently, improved gas burners havebeen designed which employ extruded hollow manifolds to carry the gasand support the flame. Such burners may be formed from aluminum andtherefore are lighter and less expensive. Furthermore, the size andcapacity of the burner can be controlled simply by cutting the extrusionto the desired length rather than altering expensive castings or using anumber of separate castings or burners. This new type of extruded burneris shown and described in copending US. Pat. application Ser. No.779,671 filed Nov. 29, I968, and invented BY Richard Weatherston.

Briefly, the new extruded gas burners described in the above-referencedcopending application are formed with an internal partition dividingthem into two elongated parallel manifolds each having a series ofspaced apertures therein which apertures face the confess-tion area.Regulated relatively highpressure gas is introduced into one of themanifolds which passes out of the apertures and generates a large mainflame for the main heating function. The second manifold receives amixture of gas and air under a relatively low-pressure which serves togenerate a small pilot flame for low heating requirements and forigniting the main flame. Experience has pointed up a number ofdifficulties inherent in this design especially in longer versions ofthe burner which to date have been made as long as l2 feet. Thelow-pressure manifold tends to have a more stable flame near the end atwhich the gas-air mixture is introduced than at the more distant end.Due to the gradual loss of pressure along the length of the pilotmanifold and the inconsistent mixing of air and gas afforded by a singlemixing device the flame characteristics along the manifold change. Thisuneven flame along the length of the burner produces uneven heating overthe length of the burner with a number of consequent disadvantages.Since the burner depends wholly or partly on the pilot flame forlow-level heating the heat output of the burner is uneven over itslength. Another difficulty is that the large volume of air and gasmixture necessary to supply a long pilot manifold requires a complicatedand expensive air and gas mixing device. The novel design of the presentinvention avoids the above described problems.

SUMMARY OF THE INVENTION Briefly, the present invention contemplatesusing an elongated extrusion with three elongated parallel manifoldsformed therein. Two of the manifolds supply the main flame and the pilotflame apertures while the third manifold accepts high-pressure gas whichis transferred to the pilot flame manifold through a series of periodicapertures along the length of the pilot manifold. The gas, thus, entersthe pilot manifold at the same pressure everywhere along the entirelength of the pilot manifold alleviating the uneven flame problem. Inaddition, another set of air admission apertures are formed in theoutside wall of the pilot manifold adjacent the transfer apertures in aone-to-one relationship so that the high-pressure gas passing form thethird manifold to the pilot manifold will aspirate air along with itfrom the air admission apertures automatically so as to eliminate theneed for the expensive and complicated prior art air-gas mixingapparatus. Thus, it may be seen that it is an object of the presentinvention to provide an improved gas burner. It is a further object ofthe present invention to provide a gas burner in which an even pilotflame is supported over the total length of the burner and in which airis automatically aspirated over the length of the pilot manifold.Further objects and advantages will become apparent upon reference tothe following description and drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partially cutawayperspective view of the main elements of the present inventive gasburner.

FIG. 2 is a cross-sectional view of the burner assembly of FIG. 1 inwhich the improved extruded manifold is shown in greater detail.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 a portion of a burnercompartment 10 is shown partially cutaway so as to provide a better viewof the burner assembly 12 mounted in compartment 10. Burner assembly 12comprises an extruded hollow member 14, upper and lower plates 16 and18, end plates 20 and 22 and a pair of diverging foraminous plates 24and 26. Foraminous plates 26 and 26 define a combustion area betweenthem where air mixes with gas emerging from a series of holes 30 inmember 14. Holes 30 connect with the large manifold 31 inside member 14which manifold receives gas from a regulated source through a pipe 32.End plates such as plate 34 in FIG. 1 serve to close the ends of themanifolds in hollow member 14. As gas enters through pipe 32, manifold31, and holes 30, air enters burner compartment 10 from the rear inFIG. 1. Some of the air passes into the rear of the burner assemblybetween plates l6, 18, 20, and 22 and through foraminous divergingplates 24 and 26 into the combustion area. Initially, the mixture isignited by a spark plug or other suitable igniting device 36. Afterinitial ignition, however, the flame is maintained by a pilot flame froma second series of holes 38 which connect with a second manifold 40.Manifol-i 40 receives gas from a pipe 44 through a third manifold 42".The unique operation of the pilot flame manifold 40 may be betterinderstood with reference to FIG. 2.

In FIG. 2, burner assembly 12 is shown in section. In order to preventan inordinate pressure drop along the length of manifold 40,high-pressure gas is introduced into manifold 42 which extends the fulllength of member 14 generally parallel to manifold 40. Manifold 42connects with manifold 40 by means of a series of transfer apertures 46.Apertures 46 are relatively small so that the gas metered into manifold40 at a slow predetermined rate. In the preferred embodiment apertures46 are formed by a no. 44 drill and spaced at approximately 24 -inchintervals. This has been found to yield a pressure in manifold 40 which.although relatively low, is consistent along the entire length ofmanifold 40 so that when the gas passes out of manifold 40 through aseries of pilot holes 38 the flame characteristics are similar along theentire length of r' nifold 4.0. Even, predictable, low-level heating isthus achieved as discussed earlier.

In order to eliminate the need for an expensive, complicated air-gasmixing apparatus to supply the pilot flame as in the past, a series ofair admission holes 50 are provided in the bottom of manifold 40. Evenpredictable, low-level heating is thus achieved as discussed earlier.

In order to eliminate the need for an expensive, complicated air-gasmixing apparatus to supply the pilot flame as in the past, a series ofair admission holes 50 are provided in the bottom of manifold 40. Onehole 50 is provided adjacent each transfer aperture 46. Thehigh-velocity gas entering through aperture 46 sucks air through hole 50into manifold 4 by means of aspiration. This flow of air mixes with thegas from aperture 46 and continues on out through pilot apertures 38assisted by the low-pressure area which exists between foraminous plates24 and 26 when the flame is burning in the combustion area betweenplates 24 and 26. Holes 50 have been made approximately one-half inch indiameter in the preferred embodiment which size has been found toprovide the proper air-to-gas ratio for proper combustion.

It may be seen that the size of the furnace can be varied simply byvarying the length of extrusion 14. Since the gas is supplied equallyalong the length of the burner and since air is aspirated equally alongthe length of the burner any length may be chosen for the burner withoutadjustments to any of the gas or air supply apparatus. Furthermore, aneven flame is produced over the length of the chosen burner due to theconstant pressure characteristics along the pilot manifold.

Transfer apertures 46 may be drilledthrough the pilot flame holes 38 ifdesired but in the preferred embodiment separate access holes 52 areprovided in manifold 42 opposite transfer holes 46. Holes 46 may bedrilled through access holes 52 and, in addition, transfer holes 46 maybe conveniently cleaned by means of access holes 52. In operation,access holes 52 are plugged by means of small sealing screws 54 toprevent escape of the gas.

I claim:

1. A gas burner comprising in combination:

an elongated hollow extrusion having a front side facing the combustionarea with two sets of longitudinally spaced outlet apertures therein;

partitions in said extrusion dividing the interior of the extrusion intofirst, second, and third longitudinally extending manifolds, said firstmanifold in communication with one of said sets of outlet apertures andsaid second manifold in communication with the other set of outletapertures; means closing the ends of said manifolds;

means for supplying pressurized gas to said first manifold and saidthird manifold; and

a series of spaced transfer apertures between said third and secondmanifolds sized and spaced to admit gas to said second manifold at acontrolled rate.

2. The apparatus of claim 1 including a series of air admissionapertures in said second manifold sized to pass air at a rate dependenton the flow of gas through said transfer apertures.

3. The apparatus of claim 2 in which said air admission aperturescomprise a series of holes positioned one each next to the transferapertures so that the flow of gas through said transfer aperturesaspirates air into said second manifold through said air admissionapertures.

4. The apparatus of claim 3 in which said extrusion has a generallyrectangular cross section with said first and second manifoldspositioned along said front side.

5. The apparatus of claim 4 in which said gas-supplying means comprise apair of inlet pipes connected to said first and third manifolds wherebygas pressure in one of the manifolds may differ from the gas pressure inthe other manifold.

1. A gas burner comprising in combination: an elongated hollow extrusionhaving a front side facing the combustion area with two sets oflongitudinally spaced outlet apertures therein; partitions in saidextrusion dividing the interior of the extrusion into first, second, andthird longitudinally extending manifolds, said first manifold incommunication with one of said sets of outlet apertures and said secondmanifold in communication with the other set of outlet apertures; meansclosing the ends of said manifolds; means for supplying pressurized gasto said first manifold and said third manifold; and a series of spacedtransfer apertures between said third and second manifolds sized andspaced to admit gas to said second manifold at a controlled rate.
 2. Theapparatus of claim 1 including a series of air admission apertures insaid second manifold sized to pass air at a rate dependent on the flowof gas through said transfer apertures.
 3. The apparatus of claim 2 inwhich said air admission apertures comprise a series of holes positionedone each next to the transfer apertures so that the flow of gas throughsaid transfer apertures aspirates air into said second manifold throughsaid air admission apertures.
 4. The apparatus of claim 3 in which saidextrusion has a generally rectangular cross section with said first andsecond manifolds positioned along said front side.
 5. The apparatus ofclaim 4 in which said gas-supplying means comprise a pair of inlet pipesconnected to said first and third manifolds whereby gas pressure in oneof the manifolds may differ from the gas pressure in the other manifold.